C# Auto Increment Primary Key with String?

Question

I am newbie to C# and programming...

When form loading primary key has to load automatically to comboBox and it has to automatically generate +1 from last value.. for example if COUNT value is 0 then it has to add like this EMP01

Here's my code:

class PrimaryKeyIncrement
{
    public void empPrimary() {
        Dbconnection ObjDb = new Dbconnection();
        ObjDb.ConnectWithDB();

        string empPri = "SELECT COUNT(EmployeeID) AS PK FROM Employees";
        SqlCommand Pri = new SqlCommand(empPri, ObjDb.conct);
        SqlDataReader rd = Pri.ExecuteReader();

        if(rd.Read()){
            string pk = rd["PK"].ToString();

            int IC = Int32.Parse(pk);
            IC++;

            string empPK = ("EMP")+IC.ToString();

            EmployeesManager EM = new EmployeesManager();
            EM.cmbEmployeeID.Items.Add(empPK).ToString();

        }        
    }

and i called empPrimary() method in EmployeesManager Form load.. There is no errors but nothing loading in the comboBox

Please help me Primary key should increase by one with String EMP

Answer 1

The actual cause of the issue you are having is because you are adding to a new EmployeeManager's combobox. You need to pass a reference to your form into your EmpPrimary

... EmpPrimary(this); //in your forms form load

public void empPrimary(EmployeeManager form){ //change the method parameters

form.cmbEmployeeID.Items.Add(empPK); // Now use the form reference in method

As plutonix has stated however, you should let the form handle the PK's itself